In electrophotographic duplicating apparatus, it is customary to adhere magnetic toner to an image-bearing surface to develop the image, to transfer the adhered toner to a copy paper, and then to fix the transfered toner to the paper. The fixation may be accomplished by pressure or heat.
In a system for fixing the toner to the copy paper by pressure, the copying paper with the toner image formed thereon is passed between two pressure-fixation rolls. In general, a conventional pressure-fixation roll for pressure-fixation apparatus is treated with a surface-hardening process and hard chrome plating process, and then ground and polished to obtain a surface roughness from 0.3 to 0.8 microns. In this connection roughness means the average height of surface irregularities. Accordingly, the surface of an image fixed under pressure by a pressure-fixation roll with a polished surface of said fine roughness is so smooth and bright as to reflect light and is difficult to see clearly in a strong light.